i just bought the tech2's and os far there great. i didnt like vipers cuz the foot pocket is kinda square and cramps your foot. overall techs are def worth the money. check out ebodyboarding.com the got the best prices and ships quick
vipers are amazing in the summer, lotz of thrust, DK, and padded top, but the pocket is too skinny for booties. get bz rubbers for the winter. Thats my setup and i love it.
As you mentioned in your question, it is a matter of personal choice or your foot shape. I will second what wontonwonton stated, except that I use Hydro Techs in cold water (when 3+mm wetsocks are in play) - not the Hydro Finz Originals or the Tech 2 models (for me, Hydro Finz are too stiff and have too much blade surface area - the Tech 2 feel great but don't give me enough traction in the water when loaded down by rubber).